A semiconductor memory device is a storage device that is achieved using a semiconductor material typically from the Group IV elements or compounds such as, silicon (Si), germanium (Ge), gallium arsenide (GaAs) or indium phosphide (InP) and the like. Semiconductor memory devices are largely classified into volatile memory devices and non-volatile memory devices.
In a volatile memory device saved data disappears when the supply of a power source cuts off. Types of volatile memory devices include a static RAM (SRAM), a dynamic RAM (DRAM), synchronous DRAM (SDRAM) and the like. In a non-volatile memory device the saved data is maintained even when the supply of a power source cuts off. Types of non-volatile memory devices include a flash memory device, a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), a resistive memory device (e.g., a phase-change RAM (PRAM), a ferroelectric RAM (FRAM), a resistive RAM (RRAM) and the like.
To satisfy the consuming public's demand for high performance and low priced semiconductor memory devices has led to increasing degrees of the integration of non-volatile memory devices. However, in the case of a two-dimensional or planar memory device, the degree of integration is limited by an area occupied by a unit memory cell. Thus, three-dimensional memory devices with vertically disposed unit memory cells have been recently developed.
Prior art memory cells are formed with common source line structures which extend perpendicularly from the substrate to a height of equal to or beyond that of adjacent channel structures. During the formation of these prior art devices a slit can be formed within the common source line structure. Moreover, during the memory cell formation processes, a concentration of F-gas can be generated which fills the slit. The filled slit can thereafter cause stress within the formed memory cell which increases the failure rate.